Draft regulator



Patented Sept. 23, 1924.

JOSEPH J. FOWDEN, 01E PHILADELPHIA, PENNSYLVANIA.

Application filed November 16,1920: So'riallN'oz 424 ,4631

1 all whom it may concern.

Be it known that I, Josnri-i J. FownnN, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia, and State of Pennsylvania, have invented certain new and useful Improvements in Draft Regulators, of which the following is a specification.

The principal object of the present invention is to provide a simple, reliable and quickly responsive apparatus for keeping constant the quantity of air per unit of time flowing through an air duct, such, for example, as communicates with a boiler chimney flue.

The invention will be claimed at the end hereof but will be first described in connection with the embodiment of it chosen for illustration in the accompanying drawings forming part hereof and in which Figure 1, is a view principally in section illustrating draft regulating apparatus embodying features of the invention.

Fig. 2, is a top or plan View drawn to an enlarged scale of parts shown at the left in Fig. 1, and

Fig. 3, is a central sectional view illustrating a modification in which external power controlled by rods of Fig. 1 is used.

In the drawings 1 is an air duct through which a current of air passes and it is shown to include a boiler chimney flue 3, is a damper and it is shown as of the apron variety, meaning that it is suspended in the fine 2, from a pivot 1, at its top edge, and it is arranged to open towards the left and into a chimney not shown. 5 is a weight mounted to move on an arm 6, pivoted at the end to an extension 7, of the damper lever 8, and adjustable connection at the other end to the lever 8 by a bolt-slot con.- nection 9. 10, is a fan arranged for revolution in the duct 1 and provided with centrifugal governor mechanism 11. In Fig. 1 this governor mechanism, or more accurately its'movable collar 12, is connected by a rod 13, having an adjusting turn buckle 1.4, with the weight 5. As shown in Fig. 3, the rod 13, carries the exhaust or relief valve 15, of a spring retracted pressure device shown to comprise a piston and cylinder 16, supplied with pressure at 17 and operated upon by spring 18; the piston being connected with the weight 5, and cylinder being suitably supported.

For the sake of a description of the mode of operation it may be assumed that the flow in the duct 1, should be appropriate for maintaining an eighth of an inch of minus water pressure in the flue 2, and that under these circumstances the damper 3, is turned towards the left and is somewhat open, and that the fan 10, is running at a certain rate and that the weight 5, is in appropriate position. If now the pressure in the flue 2, falls below an eighth of an inch, the damper tends to shut and more air will flow through duct 1 and the fan will speed up, but as the fan speeds up the governor mechanism and its connections shifts the weight towards the right and nearer to the damper so that the latter opens and thus the correct conditions are restored. If the pressure in the flue rises above an eighth of an inch, the damper opens, less air flows in the duct 1, the fan slows down, and the weight is shifted towards the left, thus tending to close the damper and restore the proper conditions. 19 is an adjustment, shown as an adjusting screw, and it serves as a means for controlling the effect of the speed of the governor mechanism in establishing the normal flow.

Another way of further describing the invention is to say that the damper 3 is adjusted to balance a certain draft, that is to say, when that draft exists the damper in consequence of it remains open to an appropriate extent. It will be assumed that when that draft exists there is one-eighth of an inch of minus pressure in the flue 2. If the pressure in the flue 2 falls below one-eighth of an inch more air will flow through the duct 1 causing the fan to speed up and the weight 5 to be shifted toward the right, changing the balance of the damper, opposing its tendency to shut and re-positioning it. The reverse of this operation takes place when the minus pressure in 2 rises. The fact that the weight is shifted changes the balance of the damper and the change in balance re-positions the damper appropriately for keeping constantthe quantity of air per unit of time flowing through the flue 2.

I claim:

1. In a draft regulator the combination of an air duct including a boiler-chimneyflue, an apron damper in the flue, a movable weight mounted on the damper to overbalance the same, a fan arranged in the air duct and provided with a centrifugal governor mechanism, and connections between the Weight and governor mechanism, substantially as described.

2. In a draft regulator the combination of an air duct including a boiler-chimneyfiue, an apron damper in the flue, a movable Weight mounted on the damper to overbalance the same, a fan arranged in the air duct and provided with a centrifugal governor mechanism, connections between the weight and governor mechanism, a spring ret acted pressure device connected with the weight, and a valve control for said device connected with the governor mechanism substantially as described.

JOSEPH J. FOWDEN. 

